Browsing by Author "Briggs, Roger M."

• Ages of the Pliocene-Pleistocene Alexandra and Ngatutura Volcanics, western North Island, New Zealand, and some geological implications 

  Briggs, Roger M.; Itaya, T.; Lowe, David J.; Keane, A.J. (1989)

  The Alexandra and Ngatutura Volcanics are the two southernmost of the Pliocene-Quaternary volcanic fields of western and northern North Island, New Zealand, northwest of Taupo Volcanic Zone TVZ. The Ngatutura Basalts are ...

  

• Ages on weathered Plio-Pleistocene tephra sequences, western North Island, New Zealand 

  Lowe, David J.; Tippett, J. Mark; Kamp, Peter J.J.; Liddell, Ivan J.; Briggs, Roger M.; Horrocks, Joanna L. (Archéo-Logis/CDERAD, 2001)

  Using the zircon fission-track method, we have obtained five ages on members of two strongly-weathered silicic, Pliocene-Pleistocene tephra sequences, the Kauroa and Hamilton Ash formations, in western North Island, New ...

  

• Depositional record of historic lahars in the upper Whangaehu Valley, Mt. Ruapehu, New Zealand: implications for trigger mechanisms, flow dynamics and lahar hazards 

  Graettinger, Alison H.; Manville, Vern; Briggs, Roger M. (Springer Berlin, 2010)

  Mt. Ruapehu, in the central North Island of New Zealand, is one of the most lahar-prone volcanoes in the world. Since historic observations began in 1861 AD, more than 50 individual lahars have been recorded in the Whangaehu ...

• Formation of magnetite-enriched zones in and offshore of a mesotidal estuarine lagoon: An environmental magnetic study of Tauranga Harbour and Bay of Plenty, New Zealand 

  Badesab, Firoz; von Dobeneck, Tilo; Bryan, Karin R.; Müller, Hendrik; Briggs, Roger M.; Frederichs, Thomas; Kwoll, Eva (AGU and the Geochemical Society, 2012)

  Magnetic iron minerals are widespread and indicative sediment constituents in estuarine, coastal and shelf systems. We combine environmental magnetic, sedimentological and numerical methods to identify magnetite-enriched ...

• Geology of the Maketu Area, Bay of Plenty, North Island, New Zealand. Sheet V14 1:50 000 

  Briggs, Roger M.; Lowe, David J.; Esler, Wilson R.; Smith, Richard T.; Henry, M.A.C.; Wehrmann, Heidi; Manning, D.A. (Department of Earth and Ocean Sciences, University of Waikato in collaboration with Bay of Plenty Regional Council, Whakatane, 2006)

  The area covered in this report on the geology of Sheet V14 Maketu 1 :50 000 includes Motiti Island and a small triangular section of the Bay of Plenty coastal lowlands from the Kaituna River mouth to Pukehina Beach within ...

  

• Stratigraphy, chronology, and correlation of the Plio-Pleistocene (c. 2.2-0.8 Ma) Kauroa Ash sequence, western central North Island, New Zealand 

  Horrocks, Joanna L. (The University of Waikato, 2000)

  The Kauroa Ash beds (K-beds) comprise a 12-20 m-thick sequence of extremely weathered, clay-rich (40-95% <4 μm clay) beds of tephra and loess, and associated paleosols. Found in isolated remnants throughout the western ...

  

• Geology of the northern Mamaku Plateau 

  Morgan, Michael Denis (The University of Waikato, 1986)

  The geology of the northern Mamaku Plateau is dominated by the rhyolitic Mamaku and Waimakariri lgnimbrites, although exposures of the dacitic Waiteariki Ignimbrite are common in river gorges. The Mamaku lgnimbrite ...

  

• Petrologic, geochemical and isotopic evolution of rhyolite lavas from the Okataina, Rotorua and Kapenga Volcanic Centres, Taupo Volcanic Zone, New Zealand 

  Bowyer, Deborah Ann (The University of Waikato, 2001)

  The Okataina Volcanic Centre (OVC) is a highly active modern silicic magmatic system at the northeastern end of the central Taupo Volcanic Zone, North Island, New Zealand. This study presents a set of petrographic, ...

  

• Weathering of basalt: geotechnical & geochemical aspects 

  Jayawardane, Merennage Padma Jayanthi (The University of Waikato, 2002)

  Geochemical influences on the geotechnical parameters of weathered Karamu Basalt are determined and the likely processes involved in basalt weathering are investigated. Geochemical and geotechnical parameters of basalt at ...

  

• Petrogenesis and evolution of alkalic basaltic magmas in a continental intraplate setting: the South Auckland Volcanic Field, New Zealand 

  Cook, Craig (The University of Waikato, 2002)

  The South Auckland volcanic field (SAVF) is situated in a continental intraplate tectonic setting and consists of silica-undersaturated alkalic basalts that erupted from about 100 centres between 1.59 and 0.51 Ma. The ...

  

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